quixos-protocol/src/capability-model/evolution.ts

import { createHash } from "node:crypto";
import type { Binding, Conformance, DependencyBinding, PersistentAttachment, WorkspaceRevision } from "./types.js";
import { validateWorkspaceRevision } from "./validation.js";

/** Content hashing is independent of JSON object insertion order, not array order. */
const compareText = (a: string, b: string) => (a < b ? -1 : a > b ? 1 : 0);
export const canonicalJson = (value: unknown): string => {
  if (value === null || typeof value === "string" || typeof value === "boolean") return JSON.stringify(value);
  if (typeof value === "number" && Number.isFinite(value)) return JSON.stringify(value);
  if (Array.isArray(value)) return `[${value.map(canonicalJson).join(",")}]`;
  if (typeof value === "object" && value !== null) {
    if (Object.getPrototypeOf(value) !== Object.prototype && Object.getPrototypeOf(value) !== null)
      throw new Error("Expected a plain JSON object");
    return `{${Object.entries(value)
      .filter(([, entry]) => entry !== undefined)
      .sort(([a], [b]) => compareText(a, b))
      .map(([key, entry]) => `${JSON.stringify(key)}:${canonicalJson(entry)}`)
      .join(",")}}`;
  }
  throw new Error(`Cannot hash non-JSON value: ${typeof value}`);
};
export const contentDigest = (value: unknown) =>
  `sha256:${createHash("sha256").update(canonicalJson(value)).digest("hex")}`;
const semantic = (value: unknown): unknown => {
  if (Array.isArray(value)) return value.map(semantic);
  if (value && typeof value === "object")
    return Object.fromEntries(
      Object.entries(value)
        .filter(([key, entry]) => entry !== undefined && key !== "displayName" && key !== "documentation")
        // These are authored data/maps, not schema nodes. A user field literally
        // named displayName or documentation is semantic and must stay in the hash.
        .map(([key, entry]) => [key, key === "defaultValue" || key === "fields" ? entry : semantic(entry)]),
    );
  return value;
};
const sorted = <T>(entries: readonly T[], key: (entry: T) => string) =>
  [...entries].sort((a, b) => compareText(key(a), key(b)));
export const conformanceIdentity = (entry: Conformance): string =>
  entry.id ?? `legacy:${entry.atomId}:${entry.interfaceRevisionId}`;

export type StorageContract = {
  id: string;
  ownerId: string;
  kind: "state" | "edge";
  digest: string;
  definition: unknown;
};
/** Automatic evolution preserves values; it never interprets migration code or
 * guesses that a new nominal message descriptor means the same representation. */
export const storageChangeRequiresMigration = (
  previous: StorageContract | undefined,
  next: StorageContract | undefined,
  oldAtomIds: ReadonlySet<string>,
): boolean => {
  if (!next) return true;
  const after = next.definition as PersistentAttachment;
  if (!previous) {
    if (after.kind === "state")
      return (
        oldAtomIds.has(after.attachedTo) && after.defaultValue === undefined && after.valueType.kind !== "optional"
      );
    return after.endpoints.some(
      (endpoint) =>
        endpoint.cardinality === "exactly-one" &&
        (endpoint.constraint.kind !== "atom" || oldAtomIds.has(endpoint.constraint.atomId)),
    );
  }
  if (previous.ownerId !== next.ownerId || previous.kind !== next.kind) return true;
  const before = previous.definition as PersistentAttachment;
  if (before.kind === "state" && after.kind === "state") {
    // Capture materializes old defaults, so changing a default affects only
    // newly constructed objects, not existing sparse state.
    const { defaultValue: _beforeDefault, ...beforeStorage } = before;
    const { defaultValue: _afterDefault, ...afterStorage } = after;
    return canonicalJson(beforeStorage) !== canonicalJson(afterStorage);
  }
  return canonicalJson(before) !== canonicalJson(after);
};
export const storageContracts = (workspace: WorkspaceRevision): StorageContract[] => {
  const result: StorageContract[] = [];
  const add = (attachment: PersistentAttachment, ownerId: string) => {
    const definition = semantic(attachment);
    result.push({
      id: attachment.id,
      ownerId,
      kind: attachment.kind,
      definition,
      digest: contentDigest({ ownerId, definition }),
    });
  };
  for (const attachment of workspace.sharedAttachments) add(attachment, "legacy:workspace");
  for (const conformance of workspace.conformances)
    for (const attachment of conformance.privateAttachments) add(attachment, conformanceIdentity(conformance));
  return sorted(result, (entry) => entry.id);
};

type GraphNode = { value: unknown; dependencies: Set<string>; reviewProviders: Set<string> };
export type RuntimeContract = {
  groupId: string;
  packageId: string;
  packageRevisionId: string;
  digest: string;
  reviewProviders: string[];
  dependencies: Array<{ id: string; digest: string }>;
};

/** Build only outbound execution dependencies. Incoming callers never retain or invalidate a provider. */
export const runtimeContracts = (workspace: WorkspaceRevision): RuntimeContract[] => {
  const nodes = new Map<string, GraphNode>();
  const node = (key: string, value: unknown) => {
    const result = { value: semantic(value), dependencies: new Set<string>(), reviewProviders: new Set<string>() };
    nodes.set(key, result);
    return result;
  };
  const conformanceKey = (atom: string, iface: string) => `conformance:${atom}:${iface}`;
  for (const storage of storageContracts(workspace)) node(`attachment:${storage.id}`, storage);
  for (const iface of workspace.interfaceImports)
    node(`interface:${iface.revisionId}`, {
      ...iface,
      members: sorted(iface.members, (entry) => entry.id).map((entry) => ({
        ...entry,
        operations: sorted(entry.operations, (operation) => operation.id),
      })),
    });
  for (const pkg of workspace.packageImports)
    node(`package:${pkg.revisionId}`, {
      ...pkg,
      semanticMajor: pkg.semanticMajor ?? 1,
      exports: sorted(pkg.exports, (entry) => entry.id).map((entry) => ({
        ...entry,
        dependencyPorts: sorted(entry.dependencyPorts, (port) => port.id),
      })),
    });
  const dependency = (parent: GraphNode, binding: DependencyBinding, atomId: string, reviews?: Set<string>) => {
    if (binding.kind === "query") {
      const pkg = workspace.packageImports.find((pkg) => pkg.revisionId === binding.packageRevisionId);
      const query = pkg?.checkedQueries?.find((query) => query.declaration.id === binding.queryId);
      if (!query) throw new Error(`Missing checked query contract ${binding.packageRevisionId}:${binding.queryId}`);
      const key = `query:${binding.packageRevisionId}:${binding.queryId}`;
      const queryNode = nodes.get(key) ?? node(key, query);
      parent.dependencies.add(key);
      for (const effect of query.effects) {
        queryNode.dependencies.add(`interface:${effect.interfaceRevisionId}`);
        for (const conformance of workspace.conformances.filter(
          (entry) => entry.interfaceRevisionId === effect.interfaceRevisionId,
        ))
          queryNode.dependencies.add(conformanceKey(conformance.atomId, conformance.interfaceRevisionId));
      }
    }
    if (binding.kind === "state") parent.dependencies.add(`attachment:${binding.slotId}`);
    if (binding.kind === "edge") parent.dependencies.add(`attachment:${binding.edgeTypeId}`);
    if (binding.kind === "creation") {
      for (const owner of binding.owners)
        parent.dependencies.add(conformanceKey(binding.atomId, owner.interfaceRevisionId));
    }
    if (binding.kind === "constructor") {
      parent.dependencies.add(`constructor:${binding.atomId}`);
      const ctor = workspace.constructors.find((entry) => entry.atomId === binding.atomId);
      const pkg = workspace.packageImports.find((entry) => entry.revisionId === ctor?.packageRevisionId);
      if (pkg) reviews?.add(pkg.packageId);
    }
    if (binding.kind !== "constructor" && binding.via) parent.dependencies.add(`attachment:${binding.via.edgeTypeId}`);
    if (binding.kind === "interface") {
      parent.dependencies.add(`interface:${binding.interfaceRevisionId}`);
      // An edge traversal may select any matching target. Conservatively include every possible witness.
      for (const conformance of workspace.conformances) {
        if (
          conformance.interfaceRevisionId === binding.interfaceRevisionId &&
          (binding.via || conformance.atomId === atomId)
        ) {
          parent.dependencies.add(conformanceKey(conformance.atomId, conformance.interfaceRevisionId));
          reviews?.add(conformanceIdentity(conformance));
          for (const operation of conformance.operationBindings) {
            let provider: Binding | undefined = operation.binding;
            const visited = new Set<string>();
            while (provider?.kind === "interface") {
              const forward: Extract<Binding, { kind: "interface" }> = provider;
              const key = `${provider.interfaceRevisionId}\0${provider.operationId}`;
              if (visited.has(key)) throw new Error("Forwarding cycle in evolution contract");
              visited.add(key);
              const target = workspace.conformances.find(
                (c) => c.atomId === conformance.atomId && c.interfaceRevisionId === forward.interfaceRevisionId,
              );
              if (!target) throw new Error("Missing forwarding conformance in evolution contract");
              reviews?.add(conformanceIdentity(target));
              provider = target.operationBindings.find((entry) => entry.operationId === forward.operationId)?.binding;
            }
            if (provider?.kind !== "package") continue;
            const revisionId = provider.packageRevisionId;
            const pkg = workspace.packageImports.find((entry) => entry.revisionId === revisionId);
            if (pkg) reviews?.add(pkg.packageId);
          }
        }
      }
    }
  };
  const binding = (parent: GraphNode, value: Binding, atomId: string, context: unknown) => {
    if (value.kind === "lifecycle") return;
    if (value.kind !== "package") {
      dependency(parent, value, atomId);
      return;
    }
    const packageNode = nodes.get(`package:${value.packageRevisionId}`)!;
    parent.dependencies.add(`package:${value.packageRevisionId}`);
    const normalized = { ...value, dependencies: sorted(value.dependencies, (entry) => entry.portId) };
    const key = `binding:${contentDigest({ atomId, context, value: semantic(normalized) })}`;
    const bound = node(key, { atomId, context, binding: normalized });
    packageNode.dependencies.add(key);
    for (const port of value.dependencies) dependency(bound, port.binding, atomId, packageNode.reviewProviders);
  };
  for (const conformance of workspace.conformances) {
    const parent = node(conformanceKey(conformance.atomId, conformance.interfaceRevisionId), {
      id: conformanceIdentity(conformance),
      semanticMajor: conformance.semanticMajor ?? 1,
      atomId: conformance.atomId,
      interfaceRevisionId: conformance.interfaceRevisionId,
      operations: sorted(conformance.operationBindings, (entry) => entry.operationId),
      ...(conformance.initialization
        ? { initialization: sorted(conformance.initialization, (entry) => entry.input) }
        : {}),
      materializations: sorted(conformance.relationshipMaterializations, (entry) => entry.memberId),
    });
    parent.dependencies.add(`interface:${conformance.interfaceRevisionId}`);
    const contract = workspace.interfaceImports.find((entry) => entry.revisionId === conformance.interfaceRevisionId);
    for (const required of contract?.requiredInterfaces ?? [])
      parent.dependencies.add(conformanceKey(conformance.atomId, required));
    for (const attachment of conformance.privateAttachments) parent.dependencies.add(`attachment:${attachment.id}`);
    for (const operation of conformance.operationBindings)
      binding(parent, operation.binding, conformance.atomId, {
        conformanceId: conformanceIdentity(conformance),
        semanticMajor: conformance.semanticMajor ?? 1,
        operationId: operation.operationId,
      });
    for (const materialization of conformance.relationshipMaterializations) {
      parent.dependencies.add(`constructor:${materialization.constructorAtomId}`);
      parent.dependencies.add(`attachment:${materialization.edgeTypeId}`);
    }
  }
  for (const constructor of workspace.constructors) {
    const parent = node(`constructor:${constructor.atomId}`, constructor);
    binding(parent, { kind: "package", ...constructor }, constructor.atomId, { constructor: constructor.atomId });
  }
  const counts = new Map<string, number>();
  for (const pkg of workspace.packageImports) counts.set(pkg.packageId, (counts.get(pkg.packageId) ?? 0) + 1);
  return sorted(
    workspace.packageImports.map((pkg): RuntimeContract => {
      const visited = new Set<string>();
      const walk = (key: string) => {
        if (visited.has(key)) return;
        const entry = nodes.get(key);
        if (!entry) throw new Error(`Unresolved execution dependency ${key}`);
        visited.add(key);
        for (const target of entry.dependencies) walk(target);
      };
      walk(`package:${pkg.revisionId}`);
      const dependencies = [...visited].sort().map((id) => ({ id, digest: contentDigest(nodes.get(id)!.value) }));
      return {
        groupId: counts.get(pkg.packageId) === 1 ? pkg.packageId : `${pkg.packageId}#${pkg.revisionId}`,
        packageId: pkg.packageId,
        packageRevisionId: pkg.revisionId,
        digest: contentDigest(dependencies),
        reviewProviders: [...nodes.get(`package:${pkg.revisionId}`)!.reviewProviders].sort(),
        dependencies,
      };
    }),
    (entry) => entry.groupId,
  );
};

export type EvolutionReview = {
  requirementDigest: string;
  decision: "changed" | "accepted-unchanged";
  rationale: string;
  agentId: string;
};
export type ReviewRequirement = {
  consumerId: string;
  providerId: string;
  oldMajor: number;
  newMajor: number;
  requirementDigest: string;
};
export type RuntimeAction = {
  groupId: string;
  action: "keep" | "start" | "replace" | "retire";
  previous?: RuntimeContract;
  candidate?: RuntimeContract;
  reasons: string[];
};
export type EvolutionReport = {
  schemaVersion: 1;
  baselineDigest: string | null;
  candidateDigest: string;
  checkerVersion: string;
  runtimeActions: RuntimeAction[];
  storageChanges: Array<{
    id: string;
    kind: "add" | "remove" | "change";
    requiresMigration: boolean;
    previous?: StorageContract;
    candidate?: StorageContract;
  }>;
  migrationRequired: string[];
  reviews: Array<ReviewRequirement & { accepted: boolean }>;
  packageChecks: Array<{ groupId: string; contractDigest: string }>;
  blockers: string[];
};

export const planEvolution = (
  baseline: WorkspaceRevision | null,
  candidate: WorkspaceRevision,
  options: { reviews?: EvolutionReview[]; allowLegacy?: boolean } = {},
): EvolutionReport => {
  const issues = validateWorkspaceRevision(candidate);
  if (issues.length)
    throw new Error(
      `Invalid candidate workspace:\n${issues.map((entry) => `${entry.path}: ${entry.message}`).join("\n")}`,
    );
  if (baseline && baseline.workspaceId !== candidate.workspaceId)
    throw new Error("Cannot evolve a different workspace");
  const candidateDigest = contentDigest(candidate);
  const checkerVersion = "quixos-evolution-v1";
  const blockers: string[] = [];
  if (!options.allowLegacy) {
    if (candidate.sharedAttachments.length)
      blockers.push("Assign legacy workspace-shared attachments to explicit conformance owners");
    for (const entry of candidate.conformances)
      if (!entry.id)
        blockers.push(`Conformance ${entry.atomId} as ${entry.interfaceRevisionId} requires an authored ID`);
  }
  const previousRuntimes = new Map((baseline ? runtimeContracts(baseline) : []).map((entry) => [entry.groupId, entry]));
  const nextRuntimes = new Map(runtimeContracts(candidate).map((entry) => [entry.groupId, entry]));
  const runtimeActions: RuntimeAction[] = [...new Set([...previousRuntimes.keys(), ...nextRuntimes.keys()])]
    .sort()
    .map((groupId) => {
      const previous = previousRuntimes.get(groupId),
        next = nextRuntimes.get(groupId);
      const before = new Map(previous?.dependencies.map((entry) => [entry.id, entry.digest]));
      const after = new Map(next?.dependencies.map((entry) => [entry.id, entry.digest]));
      const reasons = [...new Set([...before.keys(), ...after.keys()])]
        .sort()
        .filter((id) => before.get(id) !== after.get(id));
      return {
        groupId,
        action: !previous ? "start" : !next ? "retire" : previous.digest === next.digest ? "keep" : "replace",
        ...(previous ? { previous } : {}),
        ...(next ? { candidate: next } : {}),
        reasons,
      };
    });
  const beforeStorage = new Map((baseline ? storageContracts(baseline) : []).map((entry) => [entry.id, entry]));
  const afterStorage = new Map(storageContracts(candidate).map((entry) => [entry.id, entry]));
  const storageChanges: EvolutionReport["storageChanges"] = [];
  for (const id of [...new Set([...beforeStorage.keys(), ...afterStorage.keys()])].sort()) {
    const previous = beforeStorage.get(id),
      next = afterStorage.get(id);
    if (previous?.digest !== next?.digest)
      storageChanges.push({
        id,
        kind: !previous ? "add" : !next ? "remove" : "change",
        requiresMigration: storageChangeRequiresMigration(
          previous,
          next,
          new Set(baseline?.atoms.map((atom) => atom.id) ?? []),
        ),
        ...(previous ? { previous } : {}),
        ...(next ? { candidate: next } : {}),
      });
  }
  const providers = (workspace: WorkspaceRevision) => [
    ...workspace.packageImports.map((entry) => ({
      id: entry.packageId as string,
      revision: entry.revisionId as string,
      major: entry.semanticMajor ?? 1,
      node: `package:${entry.revisionId}`,
      digest: contentDigest(entry),
    })),
    ...workspace.conformances.map((entry) => ({
      id: conformanceIdentity(entry),
      revision: contentDigest(entry),
      major: entry.semanticMajor ?? 1,
      node: `conformance:${entry.atomId}:${entry.interfaceRevisionId}`,
      digest: contentDigest(entry),
    })),
  ];
  const oldProviders = baseline ? providers(baseline) : [];
  const reviews: EvolutionReport["reviews"] = [];
  for (const provider of providers(candidate)) {
    const old = oldProviders.filter((entry) => entry.id === provider.id);
    if (old.length > 1) {
      blockers.push(`Ambiguous semantic-major lineage for ${provider.id}`);
      continue;
    }
    if (!old[0] || old[0].major === provider.major) continue;
    if (provider.major < old[0].major) blockers.push(`Semantic major decreases for ${provider.id}`);
    for (const consumer of nextRuntimes.values()) {
      if (consumer.packageId === provider.id || !consumer.reviewProviders.includes(provider.id)) continue;
      const requirement = {
        consumerId: consumer.groupId,
        providerId: provider.id,
        oldMajor: old[0].major,
        newMajor: provider.major,
      };
      const requirementDigest = contentDigest({
        ...requirement,
        oldProvider: old[0].digest,
        newProvider: provider.digest,
        consumer: consumer.digest,
        checkerVersion,
      });
      const accepted = (options.reviews ?? []).some(
        (entry) =>
          entry.requirementDigest === requirementDigest &&
          ["changed", "accepted-unchanged"].includes(entry.decision) &&
          entry.rationale.trim() &&
          entry.agentId.trim(),
      );
      reviews.push({ ...requirement, requirementDigest, accepted });
      if (!accepted) blockers.push(`Semantic-major review required: ${consumer.groupId} consumes ${provider.id}`);
    }
  }
  return {
    schemaVersion: 1,
    baselineDigest: baseline ? contentDigest(baseline) : null,
    candidateDigest,
    checkerVersion,
    runtimeActions,
    storageChanges,
    migrationRequired: storageChanges.filter((entry) => entry.requiresMigration).map((entry) => entry.id),
    reviews,
    packageChecks: runtimeActions
      .filter((entry) => entry.candidate && entry.action !== "keep")
      .map((entry) => ({ groupId: entry.groupId, contractDigest: entry.candidate!.digest })),
    blockers,
  };
};